The purpose of this project is to provide detailed information of cells which respond in vitro to tissue antigens other than that of lymphocytes. Culture methods developed in this laboratory enable us to study specific lymphoctyes reactive to organ specific antigens from kidney, heart, liver and skin epidermis of syngeneic animals. The study proposed includes: 1) the minimum length of time required for the lymphocyte to recognize alloantigens, 2) the development of auto-reactive cells in the lymphoide organs, and 3) sub-populations of self-reactive lymphocytes.